Connect 110mm pvc to clay oblique junction

drainage

existing cast iron pipe into clay pipe

I want to install a toilet and replace the existing 60mm cast iron pipe with 110mm pvc

It looks as if the cast iron has been cemented into the clay pipe junction

I’m trying to avoid replacing the clay junction as it is shared with four other properties

I’m thinking of drilling holes into the cement around the cast iron to remove a plug of cement leaving a hole large enough for the 110pvc

Does this sound sensible?

I would probably either keep a stub of cast iron and connect the pvc to that or cut out the wye and put a pvc wye there instead